Conditions Of Attentional Load Research Articles

Neurophysiological biomarkers of speech-in-competition performance under different conditions of attentional load

A body of research has identified a complex integration of perceptual and cognitive processes that can modulate comprehension of speech-in-competition (SIC). However, it is not well understood how the neurophysiological correlates associated with SIC performance vary under different conditions of attentional load. Here, we analyzed the neurophysiological correlates of a SIC task using variations in masker type (spatialization, gender, language), target-to-masker ratios (TMRs), and presence of a simultaneous working memory (WM) task to manipulate attentional load during SIC performance. We used a counter-balanced block design to record EEG in each condition in 15 undergraduate young adults without hearing difficulties. SIC was assessed using the spatial release from masking task in the PART digital application. Behavioral results indicated significant differences in accuracy depending on TMR across types of maskers. We did not observe behavioral differences in SIC performance associated with the inclusion of a parallel WM task. Quantitative EEG showed a series of potential EEG biomarkers that can complement behavioral measurement in discriminating different attentional load conditions of SIC performance. These post hoc observations are discussed in relation to the extant literature and will be further investigated in future work.

The effect of verbal praise on prospective memory.

Verbal praise is often used to improve prospective memory performance in daily life. According to the motivation cognitive model, the promotional effect of verbal praise on prospective memory may depend largely on redeploying attentional resources, so its promotional effect is likely to be influenced by attention. Two groups of college students (n = 128, n = 117) participated in two experimental studies that examined this hypothesis. Experiment 1 manipulated attention load by changing the difficulty of the ongoing tasks to focus on the effect of verbal praise on prospective memory under different attention load conditions. The results showed that verbal praise promoted prospective memory performance under both attentional load conditions (low, high), but verbal praise mainly promoted the prospective component when the attentional load was low, meanwhile, verbal praise mainly promoted the retrospective component when the attention load was high. Experiment 2 altered the dependence of prospective memory tasks on attentional resources by manipulating the cue focality, further exploring the promotional effect of verbal praise on prospective memory with different types of cues under the low attention load condition. The results showed that verbal praise only promoted prospective memory when non-focal cues were used. The results of this study partially verified the motivation cognitive model.

Attentional Strategies and the Transition From Subitizing to Estimation in Numerosity Perception.

The common view of the transition between subitizing and numerosity estimation regimes is that there is a hard bound on the subitizing range, and beyond this range, people estimate. However, this view does not adequately address the behavioral signatures of enumeration under conditions of attentional load or in the immediate post-subitizing range. The possibility that there might exist a numerosity range where both processes of subitizing and estimation operate in conjunction has so far been ignored. Here, we investigate this new proposal, that people strategically combine the processes of subitizing and estimation to maximize accuracy and precision, given time or attentional constraints. We present a process-level account of how subitizing and estimation can be combined through strategic deployment of attention to maximize the precision of perceived numerosity given time constraints. We then describe a computational model of this account and apply it in two experimental simulations to demonstrate how it can explain key findings in prior enumeration research. While recent modeling work has argued that the behavioral signatures of enumeration can best be explained through a single numerosity system with a single form of representation, we argue that our model demonstrates how the traditional two-systems view of numerical representation accounts for behavioral data through coordination with a unified attentional mechanism, rather than a unifiedrepresentation.

Auditory attentional load attenuates age-related audiovisual integration: An EEG study

Studies have revealed that visual attentional load modulated audiovisual integration (AVI) greatly; however, auditory and visual attentional resources are separate to some degree, and task-irrelevant auditory information could arouse much faster and larger attentional alerting effects than visible information. Here, we aimed to explore how auditory attentional load influences AVI and how aging could have an effect. Thirty older and 30 younger adults participated in an AV discrimination task with an additional auditory distractor competing for attentional resources. The race model analysis revealed highest AVI in the low auditory attentional load condition (low > no > medium > high, pairwise comparison, all p ≤ 0.047) for younger adults and a higher AVI under the no auditory attentional-load condition (p = 0.008), but there was a lower AVI under the low (p = 0.019), medium (p < 0.001), and high (p = 0.021) auditory attentional-load conditions for older adults than for younger adults. The time-frequency analysis revealed higher theta- and alpha-band AVI oscillation under no and low auditory attentional-load conditions than under medium and high auditory attentional-load conditions for both older (all p ≤ 0.011) and younger (all p ≤ 0.024) adults. Additionally, Weighted Phase lag index (WPLI) analysis revealed higher theta-band and lower alpha-band global functional connectivity for older adults during AV stimuli processing (all p ≤ 0.031). These results suggested that the AVI was higher in the low attentional-load condition than in the no attentional-load condition but decreased inversely with increasing of attentional load and that there was a significant aging effect in older adults. In addition, the strengthened theta-band global functional connectivity in older adults during AV stimuli processing might be an adaptive phenomenon for age-related perceptual decline.

Whether attentional loads influence audiovisual integration depends on semantic associations.

Neuronal studies have shown that selectively attending to a common object in one sensory modality results in facilitated processing of that object's representations in the ignored sensory modality. Thus, the audiovisual (AV) integration of common objects can be observed under modality-specific selective attention. However, little is known about whether this AV integration can also occur under increased attentional load conditions. Additionally, whether semantic associations between multisensory features of common objects modulate the influence of increased attentional loads on this cross-modal integration remains unknown. In the present study, participants completed an AV integration task (ignored auditory stimuli) under various attentional load conditions: no load, low load, and high load. The semantic associations between AV stimuli were composed of animal pictures presented concurrently with semantically congruent, semantically incongruent, or semantically unrelated auditory stimuli. Our results demonstrated that attentional loads did not disrupt the integration of semantically congruent AV stimuli but suppressed the potential alertness effects induced by incongruent or unrelated auditory stimuli under the condition of modality-specific selective attention. These findings highlight the critical role of semantic association between AV stimuli in modulating the effect of attentional loads on the AV integration of modality-specific selective attention.

Auditory Attentional Load Modulates Audiovisual Integration During Auditory/Visual Discrimination.

Attention modulates numerous stages of audiovisual integration, and studies have shown that audiovisual integration is higher in attended conditions than in unattended conditions. However, attentional resources are limited for each person, and it is not yet clear how audiovisual integration changes under different attentional loads. Here, we explored how auditory attentional load affects audiovisual integration by applying an auditory/visual discrimination task to evaluate audiovisual integration and a rapid serial auditory presentation (RSAP) task to manipulate auditory attentional resources. The results for peak benefit and positive area under the curve of different probability showed that audiovisual integration was highest in the low attentional load condition and lowest in the high attentional load condition (low > no = medium > high). The peak latency and time window revealed that audiovisual integration was delayed as the attentional load increased (no < low < medium < high). Additionally, audiovisual depression was found in the no, medium, and high attentional load conditions but not in the low attentional load condition. These results suggest that mild auditory attentional load increases audiovisual integration, and high auditory attentional load decreases audiovisual integration.

Semantic Congruency Modulates the Effect of Attentional Load on the Audiovisual Integration of Animate Images and Sounds.

Attentional processes play a complex and multifaceted role in the integration of input from different sensory modalities. However, whether increased attentional load disrupts the audiovisual (AV) integration of common objects that involve semantic content remains unclear. Furthermore, knowledge regarding how semantic congruency interacts with attentional load to influence the AV integration of common objects is limited. We investigated these questions by examining AV integration under various attentional-load conditions. AV integration was assessed by adopting an animal identification task using unisensory (animal images and sounds) and AV stimuli (semantically congruent AV objects and semantically incongruent AV objects), while attentional load was manipulated by using a rapid serial visual presentation task. Our results indicate that attentional load did not attenuate the integration of semantically congruent AV objects. However, semantically incongruent animal sounds and images were not integrated (as there was no multisensory facilitation), and the interference effect produced by the semantically incongruent AV objects was reduced by increased attentional-load manipulations. These findings highlight the critical role of semantic congruency in modulating the effect of attentional load on the AV integration of common objects.

Multiple object-tracking isolates feedback-specific load in attention and learning.

Feedback is beneficial for learning. Nevertheless, it remains unclear whether (i) feedback draws attentional resources when integrated and (ii) the benefits of feedback for learning can be demonstrated using an attention-based task. We therefore (i) isolated feedback-specific load from task-specific load via individual differences in attention resource capacity and (ii) examined the effect of trial-by-trial feedback (i.e., present vs. absent) on learning a multiple object-tracking (MOT) paradigm. We chose MOT because it is a robust measure of attention resource capacity. In Study 1 participants tracked one (i.e., lowest attentional load condition) through four target items (i.e., highest load condition) among eight total items. One group (n = 32) received trial-by-trial feedback whereas the other group (n = 32) did not. The absence of feedback resulted in better MOT performance compared with the presence of feedback. Moreover, the difference in MOT capability between groups increased as the task-specific attentional load increased. These findings suggest that feedback integration requires attentional resources. Study 2 examined whether the absence (n = 19) or presence (n = 19) of feedback affects learning on the same MOT task across four testing days. When holding task-specific load constant, improvement in MOT was greater with feedback than without. Although this study is the first to isolate feedback-specific load in attention with MOT, more evidence is needed to demonstrate how the benefits of feedback translate to improvement on an attention-based task. These findings encourage future research to further explore the interaction between feedback, attention and learning.

Neural efficiency in basketball players is associated with bidirectional reductions in cortical activation and deactivation during multiple-object tracking task performance

Although sports expertise has been shown to have transferable cognitive benefits, it is unclear how motor expertise influences brain activity during perceptual-cognitive tasks. The aim of the present study was to investigate whether improved perceptual-cognitive behavioral task performance in individuals with well-developed motor skills is associated with characteristic cortical activation and deactivation. Blood oxygenation-level dependent (BOLD) functional MRI (fMRI) was conducted in 23 athletes and 24 age- and education-matched non-athletes performing a multiple object tracking (MOT) task with graded levels of attentional load (two, three, or four targets). Compared to non-athletes, athletes had better performance in the three- and four-target conditions of the MOT task. Less activation of the left frontal eye field (FEF) and bilateral anterior intraparietal sulcus (aIPS) and less deactivation in the bilateral medial superior frontal gyrus (mSFG) were observed in athletes compared to non-athletes. Importantly, as the attentional load was increased, differences in deactivation of the left middle temporal gyrus (MTG) between athletes and non-athletes became larger. Behavioral performance in the high attentional load condition correlated negatively with activation in the left FEF and right aIPS, and correlated positively with that in the mSFG and left MTG. Better performance in elite athletes may transfer from the sport domain to a general cognitive domain owing to higher neural efficiency, which may be represented by a bidirectional reduction phenomenon encompassing both reduced activation of areas associated with task execution and reduced deactivation of areas associated with irrelevant information processing.

Influence of sports expertise level on attention in multiple object tracking.

BackgroundThis study aimed to investigate whether performance in a multiple object tracking (MOT) task could be improved incrementally with sports expertise, and whether differences between experienced and less experienced athletes, or non-athletes, were modulated by load.MethodsWe asked 22 elite and 20 intermediate basketball players, and 23 non-athletes, to perform an MOT task under three attentional load conditions (two, three, and four targets). Accuracies were analyzed to examine whether different levels of sports expertise influence MOT task performance.ResultsThe elite athletes displayed better tracking performance compared with the intermediate or non-athletes when tracking three or four targets. However, no significant difference was found between the intermediate athletes and the non-athletes. Further, no differences were observed among the three groups when tracking two targets.DiscussionThe results suggest that the effects of expertise in team ball sports could transfer to a non-sports-specific attention task. These transfer effects to general cognitive functions occur only in elite athletes with extensive training under higher attentional load.

Temporal frequency discrimination in amblyopia.

The present study aimed to explore temporal frequency discrimination in amblyopia, and the influence of attentional load on amblyopic temporal cognition. Twenty anisometropic amblyopes, 20 strabismic amblyopes and 20 normal subjects were recruited. A flickering disk was used for visual stimuli. A two-alternative, forced-choice staircase paradigm was used to measure the temporal frequency discrimination thresholds of amblyopic eyes, fellow eyes and normal dominant eyes under reference temporal frequencies of 5, 10 and 20 Hz. The just-noticeable differences data were analyzed statistically. In addition, the temporal frequency discrimination thresholds of the subjects were measured under different conditions of attentional load. The changes in temporal frequency discrimination thresholds were compared between amblyopic and normal eyes when attention was loaded. At the reference temporal frequencies of 5 and 10 Hz, temporal thresholds of amblyopic eyes were significantly increased compared with fellow eyes (P<0.05). Regarding strabismic amblyopia, temporal thresholds of fellow eyes were increased compared with normal eyes (P<0.05). However, no correlation was identified between the temporal-frequency discrimination thresholds and the LogMAR visual acuities in amblyopic eyes. In addition, higher attentional load caused greater changes in temporal thresholds in amblyopic eyes, but the situation was not the same for lower attentional load. In conclusion, in the present study a deficit of temporal frequency discrimination in amblyopic eyes and the fellow eyes of strabismic amblyopes was identified. Furthermore, the influence of attentional load on temporal frequency discrimination in amblyopic eyes was increased compared with normal eyes.

How attention modulates encoding of dynamic stimuli in older adults

Aging is marked by memory decline that is exacerbated with attentional loading. Portraying older adults' neural functions when encoding information in conditions of high and low attentional load is a necessary step toward understanding this phenomenon. Furthermore, the information gained may be used to devise strategies aimed to prevent age-related decline in memory. To address this issue, a group of older adults underwent fMRI scanning while encoding short movies under two levels of attentional loading. High attentional load was associated with increased inter-subject correlation (inter-SC) in only a subset of prefrontal regions that were previously identified in younger adults. It was also associated with lower inter-SC in task-relevant visual regions, suggesting that as load increased, visual processing became less synchronized across participants. Critically, while we have shown that inter-SC in the dorsal posterior cingulate cortex (dPCC) was increased for younger adults at high load, older adults did not generally show this effect. However, those older adults who did display this pattern also displayed a 'younger-like' memory profile. These results point to a pivotal role of the dPCC in the interplay between attention and memory across the lifespan.

Motion and position shifts induced by the double-drift stimulus are unaffected by attentional load.

The double-drift stimulus produces a strong shift in apparent motion direction that generates large errors of perceived position. In this study, we tested the effect of attentional load on the perceptual estimates of motion direction and position for double-drift stimuli. In each trial, four objects appeared, one in each quadrant of a large screen, and they moved upward or downward on an angled trajectory. The target object whose direction or position was to be judged was either cued with a small arrow prior to object motion (low attentional load condition) or cued after the objects stopped moving and disappeared (high attentional load condition). In Experiment 1, these objects appeared 10° from the central fixation, and participants reported the perceived direction of the target's trajectory after the stimulus disappeared by adjusting the direction of an arrow at the center of the response screen. In Experiment 2, the four double-drift objects could appear between 6 ° and 14° from the central fixation, and participants reported the location of the target object after its disappearance by moving the position of a small circle on the response screen. The errors in direction and position judgments showed little effect of the attentional manipulation-similar errors were seen in both experiments whether or not the participant knew which double-drift object would be tested. This suggests that orienting endogenous attention (i.e., by only attending to one object in the precued trials) does not interact with the strength of the motion or position shifts for the double-drift stimulus.

How acute stress may enhance subsequent memory for threat stimuli outside the focus of attention: DLPFC-amygdala decoupling

Stress-related disorders, e.g., anxiety and depression, are characterized by decreased top-down control for distracting information, as well as a memory bias for threatening information. However, it is unclear how acute stress biases mnemonic encoding and leads to prioritized storage of threat-related information even if outside the focus of attention. In the current study, healthy adults (N = 53, all male) were randomly assigned to stress induction using the socially evaluated cold-pressor test (SECPT) or a control condition. Participants performed a task in which they were required to identify a target letter within a string of letters that were either identical to the target and thereby facilitating detection (low distractor load) or mixed with other letters to complicate the search (high load). Either a fearful or neutral face was presented on the background, outside the focus of attention. Twenty-four hours later, participants were asked to perform a surprise recognition memory test for those background faces. Stress induction resulted in increased cortisol and negative subjective mood ratings. Stress did not affect visual search performance, however, participants in the stress group showed stronger memory compared to the control group for fearful faces in the low attentional load condition. Critically, the stress induced memory bias was accompanied by decoupling between amygdala and DLFPC during encoding, which may represent a mechanism for decreased ability to filter task-irrelevant threatening background information. The current study provides a potential neural account for how stress can produce a negative memory bias for threatening information even if presented outside the focus of attention. Despite of an adaptive advantage for survival, such tendencies may ultimately also lead to generalized fear, a possibility requiring additional investigation.

An Eye Movement Study on the Relationship Between Multiple Implicit Sequence Learning and Attention

The purpose of this study was to explore the relationship between multiple implicit sequence learning and attention. A one-factor between-subjects experimental design was used, with attentional load (low vs. high) as between-subjects variable. Eye-movement technology was adopted, and saccadic reaction time was as dependent measure. Forty healthy volunteers were randomly assigned to high attentional load condition and low attentional load condition. The results showed that: (1) Saccadic reaction time in high attentional load condition was longer than low attentional load condition’s; (2) Both the primary sequence and the secondary sequence could be learned no matter whether in low attentional load condition or in high attentional load condition; (3) the sequence learning scores did not differ from primary sequence and secondary sequence. These findings suggest that there are no attentional limitations on the learning of multiple sequence learning.

Dissociating attentional effects on the N170 event-related potential of faces and body parts

Attention was manipulated sensu Lavie's perceptual load theory to short time presentations (200ms) of task-irrelevant unfamiliar unaltered faces, hands, and houses. Participants performed a letter detection task (X vs. N) under high (6 different letters) or low (6 identical letters) attentional load conditions. Letter strings were superimposed on task-irrelevant stimuli. Replicating and extending previous findings, while the typical pattern of face selectivity (faces>hands>houses) was observed under low load, N170 to faces, houses, and hands converged under high load. High load reduced N170 to faces, increased N170 to houses, and did not affect N170 to hands. These findings demonstrate that the category selectivity of N170 strongly depends on selective attention for faces and objects, while body parts and human bodies insensitive to selective attention.

多重内隐序列学习与注意的关系：来自眼动的证据

采用单因素(注意负荷：高、低)被试间实验设计，通过分心刺激操纵注意负荷，利用眼动技术，探讨注意与多重序列学习的关系。结果发现：1) 高注意负荷组的眼跳反应时长于低注意负荷组的；2) 高、低注意负荷组对主、次序列都发生了内隐序列学习；3) 主、次序列的内隐学习量差异不显著。研究结论：多重内隐序列学习不需要注意参与。 The relationship between implicit sequence learning and attention was one of the basic questions in the study of implicit learning. Forty healthy volunteers were randomly assigned to high attention load condition and low attention load condition. Our data showed that: 1) Saccadic reaction time in high attentional load condition was longer than low attentional load condition’s; 2) primary sequence could be learned under both high and low attentional load condition; secondary sequence could be learned under both high and low attentional load condition; new sequence could not be learned under neither high nor low attentional load condition; 3) the sequence learning scores did not differ from primary sequence and secondary sequence. These findings suggested that there were not attentional limitations on the learning of multiple sequence learning.

Pupil size directly modulates the feedforward response in human primary visual cortex independently of attention

Controversy revolves around the question of whether psychological factors like attention and emotion can influence the initial feedforward response in primary visual cortex (V1). Although traditionally, the electrophysiological correlate of this response in humans (the C1 component) has been found to be unaltered by psychological influences, a number of recent studies have described attentional and emotional modulations. Yet, research into psychological effects on the feedforward V1 response has neglected possible direct contributions of concomitant pupil-size modulations, which are known to also occur under various conditions of attentional load and emotional state. Here we tested the hypothesis that such pupil-size differences themselves directly affect the feedforward V1 response. We report data from two complementary experiments, in which we used procedures that modulate pupil size without differences in attentional load or emotion while simultaneously recording pupil-size and EEG data. Our results confirm that pupil size indeed directly influences the feedforward V1 response, showing an inverse relationship between pupil size and early V1 activity. While it is unclear in how far this effect represents a functionally-relevant adaptation, it identifies pupil-size differences as an important modulating factor of the feedforward response of V1 and could hence represent a confounding variable in research investigating the neural influence of psychological factors on early visual processing.

Theta burst stimulation improves overt visual search in spatial neglect independently of attentional load

Visual neglect is considerably exacerbated by increases in visual attentional load. These detrimental effects of attentional load are hypothesised to be dependent on an interplay between dysfunctional inter-hemispheric inhibitory dynamics and load-related modulation of activity in cortical areas such as the posterior parietal cortex (PPC).Continuous Theta Burst Stimulation (cTBS) over the contralesional PPC reduces neglect severity. It is unknown, however, whether such positive effects also operate in the presence of the detrimental effects of heightened attentional load.Here, we examined the effects of cTBS on neglect severity in overt visual search (i.e., with eye movements), as a function of high and low visual attentional load conditions. Performance was assessed on the basis of target detection rates and eye movements, in a computerised visual search task and in two paper-pencil tasks. cTBS significantly ameliorated target detection performance, independently of attentional load. These ameliorative effects were significantly larger in the high than the low load condition, thereby equating target detection across both conditions. Eye movement analyses revealed that the improvements were mediated by a redeployment of visual fixations to the contralesional visual field.These findings represent a substantive advance, because cTBS led to an unprecedented amelioration of overt search efficiency that was independent of visual attentional load.

Perceptual load of divided attention modulates auditory-motor integration of voice control

The present study sought to examine how the auditory-motor processing of feedback errors during vocal pitch regulation is modulated as a function of divided attention. Subjects were exposed to pitch perturbations in voice auditory feedback and flashing lights on the computer screen, during which they were asked to divide their attention to both auditory and visual stimuli by counting the number of both of them. The presentation rate of the visual stimuli (inter-stimulus intervel) was manipulated to produce a low, intermediate, and high attentional load. The results revealed that, as compared to the low and intermediate attentional load conditions, the high attentional load condition elicited significantly smaller magnitudes of vocal responses but larger amplitudes of N1 and P2 responses to pitch feedback perturbations. These findings demonstrate the effect of attentional load on the auditory-motor processing of pitch feedback errors during divided attention, suggesting that perceptual load of visual attention interferes the attentional modulation of auditory-motor integration in voice control.